Paul Scholes and his 'good friend' Ryan Giggs, during happier days at Old Trafford in 2010. Photograph: John Peters/Man Utd via Getty Images

Football fans everywhere love a good conspiracy theory, so here are the beginnings of one over which to chew (warning: may be half-baked). The reclusive Paul Scholes, a good friend of Ryan Giggs who appears to have been marginalised as both a player and coach by David Moyes, makes a surprise appearance on Sky Sports to help analyse a Manchester derby. With the kind of ruthless no-frills precision that marked out his passing as a player, he takes a scalpel to his former team's many shortcomings under the post-Ferguson regime: lack of pace and penetration, questionable selections, underperforming big-name purchases, a manager that still doesn't know his best side.

In mitigation, Scholes cites extenuating circumstances and says the club has "got to stand by" Moyes, but the tacit criticism is clear. Another grenade sent rolling into a dressing room rumoured to be approaching the brink of mutiny, perfectly weighted by one of United's respected players, not only of recent years but all time. Considering how reluctantly and infrequently Scholes airs his views in public, it's only natural to question the timing of Tuesday night's TV appearance and headline-making comments. Marouane Fellaini? "You'd expect better to be honest". Last night's starting 11? "Toothless". Juan Mata? "Quality ... in his right position." Cited in Sir Alex Ferguson's latest autobiography as "a man of excellent opinions", Scholes was always going to cause a stir.

Scholes' most high-profile recent and equally revelatory screen excursion was in the excellent Class of '92 documentary last year, alongside Gary and Phil Neville, and other club stalwarts who learned at Sir Alex Ferguson's knee. Now a respected pundit and Manchester United coach respectively, some insight into the two brothers' private, possibly contrasting ruminations on Tuesday night's man of the match performance from their good friend and former team-mate would be interesting to glean. With the Old Trafford natives growing increasingly restless with their manager's apparent haplessness, Scholes' comments will do little to silence whispers of an imminent Machiavellian revolt masterminded by some of the club's most faithful servants.

Of course, as unlikely as it seems, there is every chance that the famously publicity-shy Scholes simply fancied an evening of green room hospitality, pampering by makeup and a seat in front of sweltering TV lights offering forthright opinions to the Sky anchor Ed Chamberlin along with his fellow analyst Graeme Souness.

It's also far from inconceivable that he's so stereotypically "northern" that mouthing the kind of bland, obvious and uncontroversial opinions for which so many more experienced analysts are renowned is simply beyond him.

What is hard to countenance is that such a shrewd and intelligent man can be unaware of the media hubbub his influential comments would generate, which once again leads to the question: why would somebody so obviously averse to courting publicity bother pouring petrol on the flames of dissatisfaction already threatening to engulf Old Trafford?

On an evening of derby day humiliation when a section of United fans publicly turned on the watching Sir Alex Ferguson for his choice of successor, it was reported that Moyes couldn't get out of the press room fast enough when the subject of Scholes' criticism of Juan Mata was raised in his post-match media briefing. He replied that he thought Mata had played well in defeat and promptly walked out of the door. Quite what he'll make of the rest of the Old Trafford hero's blunt and astute appraisal of the shortcomings he so often seems at a loss to rectify is anyone's guess, although he may at least gain a sliver of much-needed consolation and amusement from the encore of punditry's new star-turn. Scholes' assault on Arsenal was predictably two-footed, but it's his softly spoken criticism of United that will leave the scars.